Why do hybrid battery control module connectors get corroded?

I'm not here to compete with anyone. All I come here for is to discuss problems and hopefully find solutions. Unfortunately, I seem to have an absorption limit on how much nitpicking I can take.

 

The devil is in the details. There is no need to feel threatened, just enjoy the ride.

 

Exactly... Nit-picking is a great way to get rid of all the nits you didn't even know you had. People need to learn to accept borderline trolls and enjoy their company rather than get upset at them.

 

Not so great when the purpose is to get you to react unfavorably.

 

Which is essentially the definition of a troll. The question is how many are on this forum and who are doing it intentionally versus subconsciously.

This thread has several who have been called trolls at one time or another.

 

Some people go to a forum to just to troll someone into reacting. Their trick is to troll up to the line without getting kicked, but getting someone else kicked is their "win."

 

Most curiously, my first post in this thread that involved Paul in any way was #31, where I was agreeing with Paul, because T1 Terry had just replied to Paul's post about electrolysis by limiting the concept to the dissimilar-metals case, but Paul had it right for understanding an extraneous source of voltage can also do the trick.

Then Paul replied to my agreement by nitpicking it.

 

I live in a magical world where there's no such thing as reacting unfavorably.

 

Something I hadn't thought about to bring into equation, these same wires are used for module balancing, so at times, current would also flow along what is basically a signal wire .....

Never a good idea, voltage sensing should be conducted on a different path to balancing, to both avoid creating and unwanted resistance in the voltage sensing cables as well as not affecting the voltage being sensed .....

I would say a better system, as individual cell voltages can't be sensed easily, voltage sensing per module, so the faulty module can be determined easily ...... no idea if this is how systems like the various "spy" systems work or the reconditioning systems .... which I can't see working very well without the electrolyte level being topped up and the pressure release valve being unstuck so the max 80 psi works as designed.

T1 Terry

 

I don't believe they are used that way, no. They are purely for voltage sensing.

 

I am sure that competent engineers would not find this problem insurmountable. While planned obsolescence can never be quite proved, it does provide a significant revenue stream, regardless.

 

Care to enlighten use on how the Prius balances the modules, if it isn't through the only wire connected to each two module group?

T1 Terry

 

I
n Toyota Prius hybrid vehicles, the battery modules are designed to self-balance, meaning the car's computer manages the voltage differences between cells during charging and discharging. If a Prius battery pack is out of balance, it will likely trigger an error code, but the system is designed to correct this itself under normal operation. While manual balancing is not typically necessary, tools like the Dr. Prius app can help monitor battery health and identify potential issues.


Google Search

 

This is from Google's A I

Yes, the Toyota Prius has a built-in system to balance the modules within its traction battery. The car's computer monitors and manages the charge and discharge of individual battery modules to maintain an even voltage across the pack. This balancing process helps to maximize the battery's lifespan and performance.
Here's a more detailed explanation:

• Monitoring and Management:
  The Prius's hybrid control system constantly monitors the voltage of each battery module.
• Balancing Mechanism:
  When the system detects a voltage difference between modules, it employs a balancing mechanism. This mechanism may involve slightly overcharging the lower voltage modules or discharging the higher voltage modules to bring them closer to the average voltage.
• Passive Balancing:
  The balancing is typically passive, meaning the system doesn't actively move energy between modules. Instead, it relies on subtle adjustments to the charging and discharging rates of individual modules to achieve a balanced state.
• Importance of Balancing:
  Proper balancing is crucial for preventing premature battery degradation and ensuring optimal performance and longevity. Unbalanced modules can lead to reduced capacity, decreased power output, and potentially trigger warning messages or limp mode.

Still none the wiser, some sources even claim that each module has a relay that can limit charging and discharging ..... I can call that one B/S after cutting a number of modules up to determine if it were possible to voltage sense each of the 6 cells in each module and improve the venting system and electrolyte fluid transfer to any module that needed topping up on an automated basis ..... the problem is oxygen entering the modules and this has a detrimental effect on the electrolyte ......

Probably the only way of knowing if the modules are balanced via those small wires, is a hall effect sensor around each wire and a data recorder attached ...... I don't want to know bad enough to bother going down that path

If I do go down the path of fitting the Gen 2 transaxle into my '74 VW Kombi,I'll be fitting the Zombie inverter board so I can drive MG1 and MG2 and I'll build a much higher voltage battery pack so I can bypass the Buck/Boost converter.

T1 Terry

 

Firstly, we all know that these AI LLM systems are infallible, right?

Secondly, there is no mention of any differentiation in the way Lithium modules are handled versus NiMH modules.

Next:

With respect to NiMH (which is what Gen 2 uses), what is this balancing mechanism, and how is that achieved when all modules are in series?

 

There have already been years of study of that battery ECU.

The quite different battery ECUs that Toyota builds for their lithium-battery cars probably do include balancing over the per-cell wires. Those batteries and ECUs have wires to every single cell in the pack (one of the reasons some aftermarket Lithium-for-NiMH retrofits relying only on the car's original NiMH-specific battery ECU have been the subject of safety discussions).

Because Toyota's wires to an NiMH pack are twelve cells apart anyway, the only 'balancing' they could be used to do would be between different series strings of twelve cells. To do anything like that and call it 'balancing', you'd have to already be relying on NiMH's relative tolerance for slight overcharge. You can charge a series string until the last cells in it reach full charge, and the others that got there first don't mind much.

But if you're going to take that approach with strings of 12 cells anyway, might as well just take it with the whole pack. Lithium chemistry is not ok with that approach, but with NiMH you can get away with it.

A new PriusChat phenomenon in the last year or so has been people replying to a technical point in a thread by coming back and posting something they were able to prompt an AI chatbot to write about it.

AI chatbots are great fun, amazingly capable of writing stuff in quite convincing imitation of internet content they have slurped in, and writing it to satisfy the prompts they are given. It's like having a friend who's a top-rate bullshitter and can do super-fast google searches.

But they haven't made a great showing so far at understanding technical details of a particular model and year of car. There's really no way they could; they've slurped in masses of internet content on masses of different cars, where the content doesn't always clearly state the model or year it pertains to. And in the case of a Prius, say, all of the most complete and accurate information is on TIS behind the paywall, where the chatbot most likely has never seen it.